Pulse
by CelestialFeathers999
Summary: When an accident took her best friend, Aria's, life, Luka's world was filled with endless grief. Upon learning that Aria's heart had been donated, all she could feel was rage. Miku was only grateful to have experienced a miracle and survive, with the generosity of her mysterious donor. What she didn't expect, was to meet a girl who appeared to hate her.
1. Calamity

I

Pain. Searing, hot pain. She couldn't move, couldn't breathe. It was like her lungs were filled with lead and the ringing noise in her ears threatened to drive her mad.

The door. She needed to open the door to escape. Eyes watering from the effort, she reached for the handle, only to find the airbag in front of her holding her firmly in place. Instinctively, she struggled against the suffocating pressure, causing an excruciating pain to shoot up her left ribcage.

Her vision blurred and the ringing in her head grew louder still. A shrill siren pounded her eardrums. The sharp smell of gasoline, the nauseating feeling of her lungs slowly giving out and the blurry lights she could make out through the damaged windshield…everything was pure, overwhelming agony.

' _Quick, lift her out. Get the machinery for the driver's side. I think it's stuck…'_

The world was fading…away…

0

" _Mr. and Mrs. Aurelius, your daughter was part of a collision near Exit Thirty-Two on Highway Nine. She is in critical condition at Central Hospital right now. Please make your way here as soon as possible."_

A phone call that had barely lasted thirty seconds changed their lives forever.

Piko held his wife close as she cried into his shoulder, trying to keep calm for her sake, as he eyed the bright red sign that read 'In Operation'.

Only four hours ago, his daughter had been laughing as she waved a hasty goodbye to him, her long, white hair bouncing along to her strides.

He couldn't imagine what she looked like now, on a cold table, with masked doctors rushing around her, trying to mend the grievous wounds that were quickly draining her of precious life.

She was only eighteen, excited to be starting university with her best friend and dreaming of a bright future. Piko could never forget the determination that burned in her eyes whenever she spoke of making change in the world. He'd always taught her modesty but in those moments, he couldn't help but feel proud that he'd raised such a wonderful and talented daughter.

He had such high hopes for her and tough expectations to challenge her with. But now, all he wanted was to see her happy and healthy.

Piko's eyes drifted to the room down the hall. A stinging guilt pierced his heart. He had been so worried about his own daughter that he hadn't even checked up on…

Giving his wife a tight hug, he stood up and motioned at the other side of the wing. She understood immediately, and let him go, fixating her glassy eyes back onto the closed doors in front of her.

0

 _[beep…beep beep…..]_

Luka woke to a cacophony of noises. The mask covering her face made strange whirring sounds as it pumped air, forcing her lungs to function. Some sort of monitor to her left was beeping obnoxiously. She opened her eyes slowly, squinting as the white ceiling burned into her eyes.

 _Where am I…?_

An annoying fog was clouding her thoughts. Everything felt out of sync and she couldn't move at all. Her chest was throbbing dully but it was like the rest of her body had disappeared.

… _Aria…_

She wanted to know…what?

 _Sleepy…so sleepy…_

She couldn't remember.

Something bad had happened…something terrible…

She had to know.

 _Move…Move…! I need to go…_

"Oh, you're awake! That's a relief. I know you must be worried but you can't get too agitated right now. Sorry to do this but…"

 _No…let me go…don't….! Ah…_

Her eyelids were so… _so_ heavy. The light above her dimmed until all she saw was black again.

The darkness was familiar and comforting yet despair was the only emotion that filled her as she drifted off.

 _Please…let her be safe…_

0

"How is she?"

"She's fine, stable." The nurse held a shushing finger to her lips as Piko entered. "Woke up just now."

"That's good…that's good…" Piko let out a sigh and buried his head in his hands.

The only fortunate thing about this whole situation was that Luka had only suffered comparably light injuries. She was like a second daughter to him and he knew he wouldn't be able to take it if her life was in danger too. According to the doctors, she had broken a rib and fractured another two from the impact and dislocated her shoulder. Other than a minor concussion, from when the car swerved out of the lane and collided against a tree, she had no cranial injuries.

"It must be hard…" The nurse watched Piko nervously. She had been in training until not too long ago and this was the first time she dealt with patients from such a serious accident alone. She had no idea what she should say, if anything at all.

"Yes…her parents were worried sick…" Piko answered mechanically, but his thoughts were elsewhere.

'… _the truck came from the left. Most of the damage was done on the driver's side, which is where your daughter was sitting. Even if we're lucky, it's most likely that she's retained permanent damage to…'_

He clenched his fists and willed the doctor's words out of his mind. There was no point thinking about that now. He had to have hope. He had to-

"Aurelius! Mr. Aurelius?!"

He looked outside to find a nurse walking towards him with panicked footsteps. The doors of the operating room were open and Piko spotted the doctor, speaking to his hysterical wife with a well-practiced expression of apology. The look in their eyes and the strain in their voices could only mean one thing.

In that moment, he knew it was over.

0

"Please doctor, you have to save her!" A woman sobbed and clung tightly to the man in the white cloak.

"I'm sorry Mrs. Hatsune, but this is out of my control. There's nothing we can do either if we can't find a donor in time and I've already contacted the necessary parties…" The doctor spoke softly and tried to gently unclasp the woman's fingers from his clothes.

"But you said…you said she only had a few hours left. Why, doctor? She was fine for so long…just why?!" The woman's words, slurred by her wails, were barely coherent.

"Miroku…be reasonable now." Her husband stepped forward and pulled her away. "We've always known that this might happen, haven't we? She was lucky that she managed to live so long without any major problems…"

"I don't care, Shigure! I just want my baby to be safe…Oh Miku…"

The doctor sighed and swept his gaze from the sleeping girl on the cot to her weeping parents.

She was one of the youngest patients he'd ever had. The girl looked peaceful, lying there on the pristine, white sheets, with her teal hair cascading down her back. Her breathing was so even and smooth that it was hard to believe they were racing time for her life.

Hatsune Miku…she'd been his patient for over a decade. Born with a deformed valve in her heart, Miku's life could end at any moment. But apart from the occasional visit from the cheerful girl for chest pains, she had never encountered any serious problems…until now.

The doctor gritted his teeth and swallowed the uncharacteristic melancholy that rose in his throat. He rarely felt attached to his patients, but Miku was different. She'd always looked to the future, despite her condition and something about her just brought out the best in everyone else.

He wanted to treat her case with the same objectivity as he did with the rest but he undeniably cared. Yet there was nothing he, or anyone else, could do for now but wait. They had hoped that Miku would live out her life with only minor health issues but her heart betrayed their wishes. The valve had given out and the muscle that contained it became a useless mass of pulsing flesh. Without a transplant, it would soon destroy her body.

Miku's eighteenth birthday was only in a few weeks. The thought aimlessly drifted into the doctor's mind. Even though their monthly check-ups didn't allow much room for idle chatting, he still felt her anticipation at becoming an adult. But for her to live till then…she needed someone's heart.

But who would be willing to give up something so precious?

He wondered.

And he hoped.

And he waited.

0

' _I'm sorry but…there's no way to reverse the damage done to her brain. We've tried everything we can but…Mr. Aurelius, your daughter is…'_

Braindead.

That's what the doctor had called it.

Somewhere deep inside, Piko wanted to believe that they still had a chance; that his little princess was still alive. Because she still breathed and her heart beat the same youthful rhythm it always had. But she would never open her eyes again, that much he understood.

He blinked at the motionless form on the bed.

Was that body that 'lived' on…really Aria?

He couldn't convince himself that it was.

Aria was the way she called him 'dad', the way she liked to sing, the way she stuttered when she got angry and the way she shyly greeted strangers. She was much more than the girl left here: a mere shell.

No matter how hard it was to accept, he needed to face the truth.

"I can't believe…she's gone…" Beside him, his wife finally croaked out a heartbroken whisper.

"I know…I know…" His chest squeezed at her hoarse voice. Piko didn't dare turn to look at her face, knowing that seeing her sadness would only wreck him further. He opened his mouth and searched for words that would comfort both of them but before any sounds escaped his throat, they were interrupted by a polite knocking.

"Come in."

"I'm sorry to disturb you again so soon, Mr. and Mrs. Aurelius but there's been a new situation." It was the doctor who operated on Aria. He looked truly apologetic for breaking his earlier promise that they'd have until the next morning alone with their daughter.

"What is it?" Piko questioned dully. He was so tired of everything. If only he could just close his eyes and let go.

"I want to…ask you for permission for your daughter to become an organ donor."

"What?" The doctor's timid words sounded hollow in the quiet room. Piko felt something stir in his heart; indignation, perhaps. But he was too numb to react in any way other than mumble that word.

"How could you ask such a thing?!" His wife began sobbing again, her voice rising with every syllable. "You want to take her organs…but she's…shes's…!"

"I…" The doctor swallowed and took a deep breath, "I'm truly sorry for your loss and we normally would give you more time to grieve…but I just received a request from our cardiology department. Another life is in danger; a girl. She's only seventeen and without a transplant…she will die…very soon. Please try to understand…"

"But why my daughter? Surely there are other donors? Other patients here? Just…why her…?"

"There isn't time to contact donors outside of this hospital and I'm afraid your daughter is the only one with a matching blood type here."

Piko felt faint. The doctor was looking at them with a mixed expression of expectation and helplessness. At their silence, he spoke again, this time with more urgency.

"Please consider this…please. Your daughter…she…she will have to be taken off life support soon. If you could save a life with her before that…if you could spare another pair of parents from the pain you're feeling now-"

"But…"

Piko stayed silent and rubbed his wife's shoulders as she mumbled an incoherent string of words. It was strange but the moment the doctor proposed the idea, he felt a calmness wash over him.

He thought about the doctor's words.

He thought about Aria and her dreams of one day becoming a doctor and saving people.

He thought about the precious life support that kept the shell of his daughter breathing.

It hurt…the raw, stinging pain threatened to tear him apart. But he knew what he had to do.

"I…agree to it, doctor." His voice was thick and sounded alien to even himself. "It's what Aria would've wanted…"

"What are you doing…Piko?!" A vice-like grip pulled at his arm and he turned to stare into his wife's bloodshot eyes.

"It's what she would've wanted…" He repeated slowly. "Just think about it…it's what she would've wanted!"

Without realizing, his voice had raised to a shout. Startled, his wife let go of his arm. Piko refused to look away, forcing her to keep eye contact until the fear and confusion in her eyes softened into a tortured understanding. He was right. Of course he was. No one knew his little princess better he did.

Defeated, she hung her head and stood limply at the side as Piko held out a hand to receive the papers the doctor had prepared.

"If I may ask, doctor…what organ…what organ does that other girl need?"

"Her heart, Mr. Aurelius. You will be donating a heart."

Nodding, he breathed in deeply and pressed down on the paper with the tip of his pen. Black ink spread across the page, staining the pristine, white paper. There was no going back.

"Her heart huh…" he mused to himself, "Then I suppose that lucky girl will be blessed with the love my dear Aria once held for the world…"

"Thank you so much, Mr. Aurelius…really…you don't know how generous…how precious..."

"Just hurry and go." Piko's lips twitched as he tried to smile. A tear rolled down his cheek, disappearing into the light stubble that his daughter used to be so fascinated with. "You still have a life to save, don't you, doctor?"

"Yes. Thank you…" Giving them one last nod, the doctor held the papers close to his chest and turned to leave. As he reached the door, Piko's wife, who had been silent for quite a while, called out.

"O-one last question, doctor…" her voice trembled with grief but there seemed to be a steely determination behind her words, "…that girl…what is her name?"

"Miku." The doctor lifted his head to meet eyes that were filled with tears, agony and resignation. "Her name is Miku."

* * *

 **A/N:**

I haven't been writing much but...welp...here we go :'D

This story was a request by KagamineCraze


	2. Meeting

**A/N:**

Almost forgot I had to upload this lol

CinderBurn: The concept isn't my own but I'm glad you like it ^^

Psykoakuma: Yeah...the overall mood of this fic is going to be a bit depressing but...well, you'll see~

KagamineCraze: Here's chapter two :P

* * *

II

When I woke up again, there was a strange feeling in my chest.

It was different from the occasional stinging of my surgical wounds. I could feel it constantly: a powerful beating that my own heart never really managed.

Truth to be told, I never expected to live until my eighteenth birthday. Even as that day approached steadily, I still couldn't quite believe that I had survived.

Often, I'd just sit there, with my hand over my chest, feeling my 'new' heart beat. The rhythms it played were so much stronger than what had been there before and I couldn't help but wonder what my heart's previous owner had been like.

Sometimes, I'd even be filled with the compulsion to seek out her family.

Mother and father, overwhelmed with joy at my luck and the life I was blessed with, brushed aside my questions about my donor.

It was understandable, really. They'd almost lost me so it was natural that they wouldn't want to think about those dark hours of waiting in the hospital. The only fruit of my pestering was the measly fact that my donor had been a girl my age whose brain was destroyed in a car accident.

Still, my curiosity grew. Every beat of my heart was a teasing whisper, a voice telling me to search.

I would be eternally grateful to that girl and her family's generosity. Sometimes, I'd lie on my bed and think about how sad it was that our paths had crossed this way. The only things that accompanied my thoughts then were my quiet breaths and a warm beating in my chest.

My intermittent wondering coalesced into a sort of obsession until I couldn't go a moment without thinking about them. Every time my pulse quickened, I'd become distracted. It was almost scary.

The night before my birthday, I made a wordless promise to myself.

0

"I want to meet them…my donor family."

My mother's face became stern and my father looked away. We'd just had a nice day together in the park and then at the movies. And even though I knew they'd be annoyed if I asked, I was determined this time.

So sitting here, in front of a birthday cake large enough to last me a month, I made my wish loud and clear.

"Come now, dear. Do we have to? Wouldn't it be nice to just put it behind us-"

"I don't want anything else, mother." I shook my head and looked down. "Without them, I wouldn't be here to celebrate today. I want…no, I _have_ to meet them at least once in my life."

My father's booming laughter surprised me as he wrapped one arm around me and the other around my mother.

"Oh Miroku, just let our girl do it. She's certainly determined enough. And it's not like she'll run away to them. What are you so worried for?"

"Yeah, yeah…" Mother's face softened at father's lighthearted teasing, "It's just that…" She sighed and shook her head. "You know what? Go ahead. If it's really that important to you, then who am I to be telling you no?"

"R-really?" I returned mother's kind smile with my brightest grin, "Then when can we meet them? How do we find-"

"Wooah there, slow down." Father ruffled my hair and chuckled, "You're going nowhere just yet, little one. Settle down and recover from the surgery first. Health aside, we'll need to contact them too, won't we? You can't just go asking to see people out of the blue."

"Right…" The excitement that had bubbled up in my chest dissipated quickly.

"There's no need to look so depressed." Father seemed amused by my despair. "I'll request some contact information the next week when we go for your check-up. Then you can write them a message. We'll see where it goes from there, alright?"

"Okay." I nodded quickly.

"Have patience, my dear," Mother clasped her hands together and gave me a knowing look, "Now, who wants to cut this cake?"

0

Time flew by so fast.

The thought plagued Luka's mind as she stared blankly ahead.

Her unfinished homework stared back, mocking her with the irritating spaces she had yet to fill in.

She wanted to burn all of it, really. What was the point?

Only last year, she had been so passionate about pursuing a career in medicine but that felt like an eternity ago. She could no longer remember what it was like to be without a care in the world, to laugh and to dream. Everything just frustrated her nowadays.

Things were so simple before that accident.

Sometimes, she'd see a cute dog or hear a weird joke that she knew Aria would enjoy and be filled with the urge to speak to her friend, only to be reminded that she was wishing for the impossible.

Then, resonating grief would fill her and she'd curl up on the couch and wait for it to fade. Most of the time, she ended up falling asleep; which was just fine by her, because maybe, just maybe, she'd see Aria in her dreams.

 _I miss you…_

A buzzing in her hand startled her away from increasingly dark thoughts. Luka quickly blinked away the tears that had welled up in a vain display of strength, even though no one was there to watch her. The phone in her hand and was vibrating with a muted urgency. Nothing fit her current mood better than ignoring the thing but the caller displayed on the screen was one she had to answer to.

 _[Hello?]_

[…]

 _[Okay…]_

[…]

 _[I'll go…thanks.]_

[…]

 _[Bye.]_

The recipient of her best friend's heart was coming to visit.

The information Aria's parents had just given sent mixed emotions through her.

Luka knew that the Aurelius's had been in contact with the one who received their daughter's heart for several months now but she'd always pretended that such a person didn't exist. The past was painful enough without a walking reminder of what she'd lost; what they'd all lost.

 _That girl…why did she have to take a part of…_

Feelings of blame burned maliciously inside her.

Even as the rational part of her mind told her that it was wrong to think that way, Luka wanted to hate on the girl who had taken Aria's heart. It didn't matter that all she needed was someone to direct her negativity at, an outlet. Even if such anger was undeserved, she was willing to believe in it, because anything was better than the cold, numbing hurt that filled her all the time.

 _Hatsune…Miku…_

The agonizing memories she'd tried to push aside always came knocking at her door, it seemed.

Not like she wanted to forget anyways.

A dark chuckle escaped Luka's lips with the malevolent intentions that escalated uncontrollably within her. The sound was harsh and jarring in the empty room.

 _Everything you've taken from Aria…I'll make you return it all…_

0

Long teal hair tied in twin-tails and a radiant smile…to anyone else, she would've been a most loveable child.

Luka gritted her teeth and looked away from the girl talking animatedly to Aria's mother. The woman was smiling happily and wiping away stray tears, clearly charmed by the lively teen.

 _Didn't she know that this girl was…_

She couldn't help but curse in her mind. Until the moment she saw the recipient, she hadn't realized her own subconscious desire for Miku to have a vile personality. But the slight blush on the girl's cheeks from shyness reminded her too much of Aria and just one little thing made her hard to despise.

She heard a timid giggle and more sweet words from that high-pitched voice. It was such a contrast from Aria's deep and mature one.

Miku was cheerful, infuriatingly so. She said things and moved in ways Aria never would have. Just a heart changed nothing, Luka thought bitterly.

Her best friend was never coming back.

"Excuse me, Uncle, I'm going back." Standing up, she addressed the man beside her politely and headed towards the back door since Miku was blocking the front.

"Don't you want to talk to her?" Piko called out after the pink-haired girl.

"There's no point." She spat the words with contempt under her breath, not caring if it made her appear rude. Piko was practically her dad and wouldn't take offense.

She wondered why she even bothered to come today…seeing that girl just made everything worse. She felt irritated and unsatisfied.

Aria had been there since the very beginning and no one could ever replace her. That much was obvious. But Luka knew she went to see the recipient holding some sort of hope.

 _What am I looking for?_

 _Why do I feel so lost?_

It didn't matter. Going to Aria's place today was a mistake, she decided.

Forget Miku. Forget she existed.

That was what she really wanted.

 _But what if seeing her can make me feel close to Aria again?_

A little voice in her mind questioned her. She shoved the thought down angrily. It was stupid and weak to think that way.

Miku was someone else.

Aria had been so much like Luka. They were both a bit weird by society's standards, had the same taste in music and practically dreamed the same dreams. Even at a glance, the teal-haired girl she met today was nothing like them.

Bright and sunny, Miku was probably the kind of child that every parent wished they had. At school, she'd be the popular type, surrounded by friends and admirers. She was someone Luka could never relate to. At least, that was how it seemed to the pink-haired girl.

"Hey, wait…!"

A voice she loathed to hear made Luka stop in her tracks.

"What do you want?"

From the way Miku shrunk back with surprise, it was clear Luka spoke with a little more force than necessary.

 _Good. That'll teach her to stay away._

"O-oh…it's just that Mrs. Aurelius wanted me to ask you if you wanted to stay for dinner…?"

The teal-haired girl looked a little timid but still smiled shyly at Luka. She was clearly still trying to be likeable, despite the open hostility she was receiving.

 _Of course. That's what people like her did: tried to please everyone._

"Tell her that I don't." Luka replied curtly, willing for Miku to get the message and leave her alone. The teal-haired girl seemed unfazed, however, and tentatively inched a little closer.

"U-um…my name is Miku, by the way. Hatsune Miku."

"I know."

 _And I don't care._

"Ah...you're Luka right? Mrs. Aurelius told me about you. I hope that we-"

"I don't want to be friends. You should go back and have dinner with them."

Miku's lips trembled and she stumbled back, looking every bit like a kicked puppy.

A twinge of _something_ welled up in Luka's heart.

It wasn't regret or remorse, she firmly told herself as she glared at the girl in front of her. It couldn't be.

"I…I see. W-well I live pretty close to here so I'll be visiting often…I'll be…um-"

"Come to my house after dinner tonight." Possessed by an urge she couldn't begin to understand, Luka grabbed Miku by the wrist as the teal-haired girl was about to leave. "I live in that house over there with the white fence." She gestured in the general direction.

"Why should I?" Miku broke free from Luka's grasp and took a few steps back. For the first time since they met, the teal-haired girl looked a little irked. "You clearly don't want me around."

Luka fell silent and refused return the hardened teal gaze.

"You owe me." She finally answered, lips pulling up in a humourless smile.

"For what?" Miku's expression changed from friendly to haughty and apprehensive at the unreasonable request.

"You took Aria's heart, didn't you?"

"Yes…but what does that have to do with you?"

Luka shrugged. "Come or don't come. It's your choice." She gave the teal-haired girl one last dismissive look and began walking away.

Miku stared after Luka until she disappeared into her house.

"Weirdo…" She mumbled to herself and started back towards the Aurelius's house, trying to ignore the stinging hurt she felt at the pink-haired girl's words.

0

 _Why did I ask her to come?_

Luka leaned back on her couch and stared mindlessly at the ceiling.

Curiosity, probably, she answered herself. Even as her negative feelings towards the teal-haired girl persisted, Luka couldn't help but be drawn towards Miku. It was a twisted kind of comfort that she sought.

 _Aria…why did you leave me all alone…?_

Bitter. Everything tasted bitter.

Outside, the skies were fading from blazing orange to a more sinister black. Luka wondered if Miku would come at all, after how coldly she was pushed away today.

As if on cue to her question, the doorbell rang.

"Come in." Luka's voice was as emotionless as she felt. The teal-haired girl eyed her cautiously as she stepped inside.

 _It's only natural for her to distrust me…we've only just met and yet I…_

"Um…" Miku was staring at her expectantly. The pink-haired girl suddenly felt a little awkward, standing there near the door. She had invited Miku on impulse and now that she was here, Luka was a little lost as to the purpose.

"Follow me." She tried to push back the fluttering feeling in her stomach and remind herself that there was no need to feel nervous in front of this stranger. After all, it's not like she wanted Miku to like her…or be friends, as she had plainly expressed.

They sat down on the couch in silence. Luka refused to make eye contact and the two of them stared straight ahead for impossibly long.

It was then that Luka suddenly felt foolish. She wanted to deny that she was wrong and continue to curse the teal-haired girl in her mind but she couldn't do it, especially not with Miku sitting so close.

What right did she have to treat Miku like this, really?

Needing a transplant wasn't the teal-haired girl's fault. Aria and the accident…wasn't her fault.

Still, Luka couldn't bring herself to like Miku.

She snuck a glance at the girl beside her. She was sitting there, with her hands gripping the edge of the cushion. The way she bit her lip and the worry in her teal eyes betrayed the tension in her body. An odd desire came to Luka.

"Can I…ask you a favour?" She sounded strange and hoarse after the prolonged silence between them.

"H-huh? I…I guess?" Miku's eyes widened, unsure of what to make of the sudden politeness in the pink-haired girl. She had been expecting more anger-filled confrontation but Luka appeared tired, defeated even.

"Will you let me listen…to your heartbeat?"

Miku opened her mouth but the words died in her throat. How was she supposed to respond to such a request? Sure, they were the same age and Luka didn't seem threatening, despite her aggressive demeanor from earlier…but she was still a stranger. The idea of letting someone she'd only met hours ago so close...quite frankly, it made her uncomfortable.

Yet, when her eyes drifted to meet Luka's, she could almost feel her own heart break. There was so much pain and grief in those crystal blue irises. They were pleading her, asking her for something she couldn't begin to fathom. Miku could faintly detect a distant longing in her gaze. The intensity of the moment was too much for the teal-haired girl to handle and she broke eye contact. She felt her defenses peel away and her wariness melted into sympathy.

"…alright."

It wasn't just for Luka either that she agreed. Perhaps this was one of the only ways she could repay Aria. Miku felt certain of it.

Something akin to relief coloured the pink-haired girl's features and Miku jumped a little as she felt hands on her shoulders. Luka gently guided her to lie down. There was something almost fond in the way she looked at Miku.

The teal-haired girl could feel her own pulse begin to race as Luka slowly curled up against her and pressed an ear against her chest. Knowing that the other girl could hear everything only made Miku's heart pound even harder.

Miku stayed impossibly still, wound up from nerves. Luka, however, seemed to be perfectly relaxed as she wrapped an arm around the teal-haired girl's waist. Her eyes were closed, appearing at peace as she listened intently.

Miku shivered a little and tried to steady her breathing. She knew that Luka was only listening for Aria but something about the warm weight of the other girl's body pressed against hers made her feel so conflicted. Her senses seemed to sharpen all of a sudden. She could feel every rise and fall of Luka's chest and thought she smelled the faint scent of cherry blossoms in the air. Probably her hair, Miku thought hazily and resisted the urge to run her hand through the long pink hair that fell like a blanket on the two of them.

Her heart was beating so fast that it throbbed. She didn't know why it was so hard for her to calm down. The room was deathly silent, save for the sounds of their mismatched breathing, yet she could feel adrenaline coursing through her body, as if the world was on the brink of its end.

Confusing. So very confusing.

Miku suppressed the mixed emotions that ran through her. She was just a vessel for Aria's heart. That was all there was between them: a melancholy connection.

The last rays of the dying sunset were swallowed by the horizon and darkness fell upon them. To Miku, an eternity may well have passed in that room and she wouldn't have known. Her body buzzed with electricity and she was so sensitive to everything around her.

Even when Luka lifted her head and moved away from the teal-haired girl, Miku stayed in their previous position. An incomprehensible feeling of loss washed over her when the spot Luka had previously rested in felt cold.

"You should probably go now."

"Right." Her voice was breathy and weird and Miku hoped that Luka didn't notice. She felt exhausted and on edge at the same time. Her movements were clumsy and mechanical.

Miku felt the pink-haired girl nod but she couldn't make out what expression Luka wore in the dark. Probably none at all, Miku mused to herself. Because she was no longer listening to Aria and Luka didn't care for Miku. The teal-haired girl brushed off the way her chest constricted at the thought and let the other girl help her up.

Wordlessly, they walked to the door. Miku stepped outside and looked back one last time, yet she was unable to make a single sound or think of anything to say. Neither was Luka, apparently, and they merely stared at each other. Streetlights reflected dully off the pink-haired girl's eyes but Miku couldn't tell if they held less sorrow than before.

The teal-haired girl sighed and turned away, doing her best to ignore the turbulent emotions that clawed at her insides. The door closed behind her in a muffled click and Miku halted her steps.

Then she began to run in the direction of home.


	3. Fragments of the Past

III

Miku continued visiting Luka. It wasn't often, maybe only once a month when school got busy. But every time she went to see the Aurelius's, she made sure to stop by the pink-haired girl's place.

While she had become quite close to Piko and his wife, Miku still didn't know how to define the relationship between her and Luka. It sat awkwardly between acquaintances and something far beyond a regular friendship. They never really spoke to each other. Even a greeting was rare. Every time Miku visited, Luka would let her in and listen to her heartbeat on the couch like they did the first time.

If Miku wanted water, she needed only to ask and the pink-haired girl would obediently bring a glass for her. If Miku's legs became numb from sitting in the same position for so long, Luka would let her get comfortable before reclaiming the spot over Miku's heart. She never spoke more than a few words and Miku never saw her smile, not even once. Even though Luka hadn't shown any sort of hostility again, Miku's heart was constantly in her throat whenever they were together. It was as if she was expecting something but she couldn't place what exactly she was looking for. All Miku knew was that she felt _different_ around Luka. She couldn't channel any of her usual optimism, despite the overwhelming desire to lift the aura of melancholy around the pink-haired girl.

Miku never stayed for longer than an hour.

She wondered why she kept going back. Even as a way of coping, most people would find their actions bizarre. But she didn't mind.

Other than her heart condition, Miku had always been someone who never really strayed from the norm. She listened to mainstream songs and followed popular fashion trends. Although she never judged others, she'd always kept to the crowd with things like this. Still, she didn't care. Even as she questioned it herself, she accepted that this strange little ritual that repeated between them was a regular thing now.

But as time passed, her own feelings became clearer; the feelings she tried her best to shove down into a place where she herself would have trouble finding, in hopes that they would one day be forgotten…because those feelings wished for something irrational and impossible. Yet the very sentiment she tried to hide manifested itself in an arrhythmic pulsing of her heart every time Luka was near.

They couldn't continue like this forever. Miku thought about that reality far more than she should have. One day, they would part ways…and then what? It made no sense but Miku couldn't imagine what it would be like then. She was attached, no, _addicted_ , to the unusual connection they shared. Although more and more often, she found herself wishing that it hadn't been Aria that brought Luka to her. Sometimes, Miku yearned for the pink-haired girl to look at _her_.

But it was too much to hope for any sort of change…or so Miku thought.

0

She went to Luka's house earlier than usual that day.

The last of her university exams were done and Miku had decided to see the Aurelius's in the morning. It was barely afternoon when she knocked on the now-familiar doors of the pink-haired girl's house.

To her surprise, Luka didn't let her in right away. Instead, she fidgeted at the door, looking almost anxious for the first time since they met. The pink-haired girl seemed to be searching for the right words and Miku felt her heart skip a beat, knowing that Luka was trying to talk to her.

She smiled encouragingly and waited; a hesitant invitation.

"I want to show you a place today…is that okay?"

Luka's voice was low and calm, despite her flickering gaze and the way she avoided Miku's eyes. The teal-haired girl could only nod and be led along. Truthfully, she was grateful for every peaceful second they spent together, knowing that it could all end abruptly one day. Miku wondered if she even had the willpower to deny Luka of anything at this point.

Luka locked the door behind her and they were on their way. Houses and streets passed by but Miku's eyes were trained on the rose-coloured silhouette in front of her. Veering off into a secluded trail, Luka was leading them towards the centre of a park nearby.

The little path they started on eventually opened up to clearings, surrounded by trees and sports fields. Luka kept walking until they reached a quiet area of the park where a small pond shimmered under the soft light of the afternoon sun. A few ducks were preening themselves in the water, others napped on the far banks. Reeds and cattails swayed lazily with the gentle breeze. The entire place was so beautiful that it seemed like scenery out of a painting.

Luka stopped for only a second to catch her breath before circling around to the other side of the pond, where trees and other vegetation grew in abundance. Parting the foliage slightly, the pink-haired girl revealed a small river that fed into the pond. Effortlessly, she stepped over the rocks and the frothy current and waited for Miku to do the same.

The teal-haired girl wanted to mirror Luka and cross to the other side as easily as the other girl had done but she felt so much uncertainty. The gap between the riverbanks wasn't huge but it was something completely new to her. Because of her condition, Miku was never really allowed outside. To avoid straining her heart, she barely exercised, much less played around in nature like the other kids.

Seeing her hesitation, Luka's eyes softened and she extended a hand towards the teal-haired girl. Miku felt her heart swell at the gesture. She took the hand eagerly and stepped forward, relying on the exhilarating emotions that Luka evoked for strength. When she successfully crossed the river, she held on to Luka's hand for longer than necessary, pretending to be steadying herself. She was cherished the warmth that radiated from between her fingers until Luka slowly pulled away.

They didn't walk much further after that. The trees grew thick in the little island-like structure that Luka led them to. A rock lay in the middle of everything, illuminated by the sun like a hidden gemstone. It was flat and slightly sloping, a perfect, natural bench.

Sitting down, the trees were sparse enough for them to see the across the pond to the trail. A few ducks startled at their presence and escaped into the water. In the familiar silence that stretched between them, Miku couldn't help but admire the cozy hideout. It was a little wild and a little lonely but it was also idyllic and ethereal.

"This was…Aria's favourite place, when we were little." Luka finally whispered. Miku turned to find the pink-haired girl staring into the distance, looking like she was about to cry. She could feel an ache in her heart at seeing Luka like this. But a small ember of hope also ignited within her. It was the first time that the other girl had shown any emotion in front of Miku. She wanted to believe that Luka was opening up to her. The pink-haired girl didn't seem to mind her silence and kept talking. "We were always together…even back then. I hated going outdoors but she kept taking me to all these different places. Our headquarters ended up being this rock." Luka's voice cracked a little and she looked down. "When I sit here…I still feel like she'll be right next to me."

"I'm sorry…" Miku couldn't think of anything else to say. Such raw pain emanated from Luka. It made her want to embrace the pink-haired girl but she held back. Despite knowing each other for months now, Luka still felt like a stranger most of the time. After all, they never talked or exchanged anything more than mere glances. Miku realized that she had no idea _how_ to converse with Luka.

"I haven't been here since…she left…I was scared to come and face the emptiness." She looked up at Miku and carefully held her gaze. When a tear finally escaped down Luka's cheek, Miku couldn't stop herself anymore. Mustering all the courage she'd ever had in her life, she slowly reached forward. When Luka didn't resist, she wiped away the glimmering tear.

Emboldened by her small 'victory', Miku ventured even further. Leaning forward, she pressed into the pink-haired girl in a half-hug. Luka made a choked sound of surprise but didn't push her away.

Miku allowed herself to be immersed in the bittersweet taste of the moment. Her head was nestled against Luka's chest and for the first time, she heard the pink-haired girl's heartbeat and felt it speed up. Even though she knew it most likely didn't mean anything, Miku listened closely and drowned herself in the erratic rhythm, _Luka's_ rhythm.

After a long time, she felt an arm wrap around her and pull her in. Luka shook as she cried, holding Miku tightly, as if she was afraid that the teal-haired girl would disappear. Not quite brave enough to look up, Miku closed her eyes and let herself be embraced. The occasional tear would fall on the teal-haired girl's face but she stayed still until Luka's sobs faded and her breathing became even again.

No more words were said even when they left, under the weak glow of the sunset. Luka helped her across the river again and continued walking ahead. Her eyes were red but she acted as if nothing had happened.

Miku was too afraid of breaking the fragile emotions that hung between them to say anything, even words of comfort. So she followed along, like always.

It was dark when they returned to Luka's house. Miku suppressed the simmering desires inside and resigned to bidding Luka goodbye the usual way; that is, without saying anything at all.

She watched the pink-haired girl walk towards her house with weary steps. Just when Miku was about to turn away, Luka spoke.

"Next time when you come…can you stay the night?"

Too drained to try and decipher the pink-haired girl's intentions, Miku gave Luka a small smile and nodded.

"Okay."

And with that, Miku walked away, feeling somehow even more broken than before.

* * *

 **A/N:**

Finally back from vacation to update. Thanks to everyone who faved/followed/reviewed~

Next chapter will be the last one :)


	4. Your Heartbeat

IV

Since when did her feelings change?

Luka couldn't remember. But the scorn she held for Miku had all but disappeared. And maybe, just maybe, she thought she could feel her sadness lifting.

Soothing companionship and coming to terms with Aria's death…both would have been impossible without Miku. Without her previous anger, however, Luka had no idea who the teal-haired girl was to her anymore.

Just a friend?

The recipient?

Her saviour?

Miku was all three, yet Luka knew she didn't want to define the other girl with any of those titles. Ever since they visited the park together, she found it impossible to control herself when she was thinking about the teal-haired girl.

She'd replay all the times Miku visited in her mind and wonder why Miku was motivated to help her at all. Perhaps to repay Aria…perhaps not.

What bothered Luka the most wasn't how frequently she thought about Miku but the strange anxiety she'd easily get when she pondered their relationship. She always felt so self-conscious when she examined the memories of the time they spent together.

 _Why do I suddenly care so much what she thinks of me?_

The only answer that came to Luka was one she chose to ignore.

What would Miku think if she knew that the last few times, Luka hadn't been listening for Aria at all?

 _Would she find me creepy and leave?_

Luka wondered how long she could keep on lying to both Miku and herself. Still, the stakes were too high for her to speak the truth. Grief, from losing Aria, still hung over her like a dark cloud. Luka knew she wouldn't be able to take it if Miku abandoned her too. For that, she had to keep pretending, even if it was selfish, because Aria was the only way to make her stay.

0

It was almost dusk when she knocked.

"Sorry I'm a little late. Piko took me out for dinner and I thought it would be fine since I'm staying here tonight anyways. Hope you weren't waiting long." Miku's smile was no longer shy, Luka noted, but it was still so bright, like she was trying to cheer up everyone around.

She wanted to say something, a simple greeting, a quiet welcome.

As usual, Luka found herself tongue-tied and unable to speak. Refusing to let Miku notice her weakness, she closed the door behind her and boldly took the teal-haired girl's hand.

"Let's go." It was much easier to talk when she wasn't looking into those lively teal eyes.

"N-now? It's pretty dark already…"

"Yes. It won't take long."

Miku's hand was soft and cool. Luka didn't dare grip it too hard, in fear of hurting the other girl.

They traveled in a practiced silence, leaving countless streetlights behind until they reached a small playground.

Letting go of Miku, Luka sat down on a swing she had outgrown years ago. The teal-haired girl did the same beside her.

Luka didn't speak. She was still thinking about the feeling of Miku's hand in hers. It wasn't until Miku directed a puzzled glance at her that she realized she had yet to explain the purpose of their little expedition.

"Look up." She tilted her head to face the sky and bid Miku to follow. Judging by the soft gasp of surprise, the teal-haired girl had listened.

Silver specks dotted the obsidian canopy in their field of view. There were so many stars that the sky seemed to glow, despite how dark it was. Having seen it before, Luka looked away from the breathtaking scene and observed Miku, who was still entranced.

"Aria and I used to do this every year…the skies are especially clear at this time." Luka kicked at the gravel mindlessly, trying to swallow the pain of remembering Aria. Miku met her gaze and Luka felt a shiver run down her spine. She looked away and tried to regain control of her emotions.

"It's beautiful…thank you for sharing this with me."

"No…I should be thanking you." Luka looked up again to avoid Miku's eyes. "All my life…all I had was Aria. My parents were always busy with their business. I've never even lived with them, only caretakers" Luka sighed and stared at a particularly bright star. The nostalgic evening air was making her talk far too much. But somehow, she didn't mind. The thought that Aria might be watching them from among the stars comforted her. Miku seemed to be waiting for her to continue talking, so Luka did just that. "I…you could almost say that Aunt, Uncle and Aria were my only family. That's why…that accident destroyed me. And when…when the Aria became your donor…" Luka hung her head and closed her eyes, feeling shame burn her cheeks. "…I blamed you. Because I wanted to believe that she could've survived even though…"

"Hey…"

A hand gently pulled at Luka's tightly clenched one. She felt Miku tenderly unfurl her fist and slip cool fingers between hers. Her vision distorted with tears at the kind gesture.

"I'm sorry."

"I-it's okay! I forgive you…" When their eyes met, Luka could faintly make out tears running down Miku's cheeks too. The teal-haired girl sniffed and turned away. "How could I ever hold that against you…"

"I'm glad…" Luka said softly.

"You know, I never really had anyone either, other than my parents, that is. I've always been homeschooled because my heart could go out at any moment…and life was so lonely. When I met you, I thought…I hoped…" Miku caught herself and stopped. "Never mind…"

"But it's not like that anymore," Luka mumbled. Her heart began to hammer in her chest, "Now we…"

She wasn't brave enough to say it and Miku didn't push her. The teal-haired girl merely smiled at Luka, acknowledging that she understood.

 _Now we have each other._

0

Miku was exhausted when they returned to Luka's place.

They couldn't have spent more than thirty-minutes in the playground but she felt so close to collapsing. Her emotions were in turmoil and just standing beside Luka was making her want to do impulsive things.

But she couldn't.

She was afraid of losing what they had built.

So instead, the teal-haired girl focused on unpacking the clothes and other items she brought for staying overnight. Luka had shown her to the guest room and locked herself in her own bathroom first thing. Miku knew it was an excuse to get away from her. Their nerves were much too frayed tonight to do much more talking.

Changing into her nightdress, Miku turned off the lights and climbed into the bed. She wrapped herself snugly in the blankets Luka had prepared, feeling mildly disappointed to find that it barely had a trace of the pink-haired girl's scent.

She had almost fallen asleep when she heard a scuffling outside her door. The quiet footsteps stopped and started again, pacing back and forth. When she heard her doorknob turn, Miku discreetly cracked open an eyelid.

Luka was watching her with an unreadable expression. The pink-haired girl appeared to have just come out of the shower. Her hair was wet and drenching the front of the baggy nightshirt she wore. Slowly, Luka began making her way forward, stepping carefully as to not make a sound.

Miku squeezed her eyes shut and pretended to be asleep, like Luka had assumed her to be. She heard the muffled 'thump' of the other girl kneeling down and felt a light breath tickle her cheeks. It was all Miku could do to keep her breathing slow and even so that Luka wouldn't detect she was awake and very much aware of what was going on.

Soft lips ghosted across her forehead.

The kiss happened so quickly that Miku almost thought she imagined it. Blood rushed to her cheeks as her heartbeat accelerated. She was glad that she kept her hands beneath the covers because she was certain that they were shaking.

Just when she thought Luka was about to leave, warmth brushed her own lips. This time, it stayed long enough for Miku to be sure that it was neither her imagination nor a dream.

She must have made some sort of noise because Luka sounded startled and pulled back quickly. Within seconds, the pink-haired girl was gone, leaving Miku alone with the uncontrollable fervour that spread though her body.

The teal-haired girl tossed and turned for a long time that night, unable to sleep. She was burning with questions and desires that threatened to make her chest burst. But she knew all too well that she wouldn't have the courage to lay her feelings bare when morning came.

0

Luka wasn't there to see Miku home.

She left only a hastily-scrawled note under a plate of breakfast that had long since gone cold. The teal-haired girl wanted to curse Luka for being a bigger coward than she was but she was too tired to even hold on to her spite.

Miku ate quickly and called her mom to pick her up.

There was so much they had yet to sort out but Miku was certain of one thing: next time, Luka wouldn't be getting away so easily.

0

Almost a week had passed when Miku felt ready to visit again. She didn't visit the Aurelius's beforehand this time. Miku was going for Luka and Luka only.

When the door opened in front of her, she half-expected the pink-haired girl to invite her in wordlessly, like before, or even turn away.

But Luka did neither.

Instead, the pink-haired girl gingerly looked into Miku's eyes and smiled.

It was the first time she had ever seen Luka express joy and knowing that it was at seeing her…Miku felt even more breathless.

"Miku…" Luka said her name slowly, as if she treasured every syllable, "Will you…let me listen to _your_ heartbeat today?" There was something peculiar about the way that Luka asked the familiar question. When Miku didn't answer, a flash of worry entered the pink-haired girl's eyes, like she feared that the teal-haired girl didn't understand. Luka reached forward and took Miku's hands in her own, "What I mean is…not Aria…but…"

"I know." Miku leaned in and wrapped her arms around Luka's waist, until their fluttering hearts pounded erratically against each other. Drinking in the sweet taste of their first proper embrace, Miku whispered teasingly into Luka's ear, "You owe me a lot by now, don't you think?"

"I…I do."

"For stealing my first kiss like that…among other things."

Luka's cheeks reddened at Miku's words but she nodded and buried her nose into the other girl's long, teal hair.

"Then I'll stay by your side for as long as I need…as punishment."

Miku grinned and held on tighter.

"That punishment better last forever."

"Don't worry…it will." Luka ran a her fingers through Miku's hair and assured her.

 _For as long as my heart beats…it beats for only you._

* * *

 **A/N:**

Aaand it's a wrap :3

Recently, I've been trying to write shorter stories because of writer's block on my longer ones so don't be surprised if my next few stories are all around this length (10k or so words).

Thank you all for reading and extra special thanks to my reviewers. Your comments are what motivate me to write, at the end of the day ^^

Hope you guys enjoyed this ficlet!

Until next time~


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